SessionId

— This post is part of a series of monthly blog posts about all kinds of Security topics for Developers —

The HTTP protocol is stateless, meaning that the server is not required to store state information for a conversation. This simplifies the protocol a lot, but there are often situations where keeping state is desired. For example, you don’t want users to send their login credentials with each request. To prevent having to reauthenticate all the time, sessions were invented. Sessions are great because they allow the user to authenticate once, and then stop thinking about it. However, hackers also find them great, because if sessions leak, the hacker doesn’t need to authenticate either to use your account. So, how do we do proper session management and prevent session data from falling into the wrong hands?